Predicting Reagent Chiller Instability and Flow Cell Heater Failure in Sequencing Systems

ABSTRACT

The technology disclosed detects chiller system instability that reduces false alerts. A smoothed time series of chiller temperature sensor data is tested in a predefined time window for periods of stable operation below a predetermined threshold. The technology disclosed predicts that the reagent chiller is unstable if periods of stable temperature operation are less than a predetermined stability measure or if the stable reagent chiller temperature has exceeded a threshold. The technology disclosed detects flow cell heater failure over multiple cycles in a system. A time series of flow cell heater temperature sensor data is tested to determine if a count of points in a recent process cycle were recorded above a threshold. The technology disclosed determines that a flow cell heater is failing if count of points above a threshold in two consecutive cycles is less than a predetermined count.

PRIORITY APPLICATION

This application claims the benefit of U.S. Provisional application No.62/613,910 filed Jan. 5, 2018, entitled PREDICTING REAGENT CHILLERINSTABILITY AND FLOW CELL HEATER FAILURE IN SEQUENCING SYSTEMS byinventor Gregory Apker (ILLM 1004-1/IP-1661-PR). The priorityprovisional application is hereby incorporated by reference.

BACKGROUND

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also correspond toimplementations of the claimed technology.

The technology disclosed relates to sequencing systems including systemsapplying sequencing-by-synthesis technique for sequencing nucleotides. Asequencing run to identify nucleotides in molecules is an extendedprocess taking multiple days to complete. All subsystems of a sequencingmachine need to operate without errors in order for resulting base callsto be useful for downstream analytics. A difficult problem arises topredict consequential malfunctions in operation of sequencing machinesbefore and during a sequencing run. Sensors in sequencing system producereadings that are used to control operating conditions of variouscomponents. These readings are used in control loops to alter the futurestate of the system, but are not available to operators. Even if thesensor readings were available to operators, the problem of predictingconsequential malfunctions of sequencing machines would not beadequately addressed, because appropriate sensor values are notself-apparent to an operator.

The subsystems of a sequencing machine can be impacted by externalfactors including the environment in which they are operating. Thesensor readings do not identify whether an unusual sensor reading is dueto an unstable or failing subsystem or an external factor. The impact ofexternal factors is usually temporary and the subsystem performancereturns to normal level when the external factor is removed. It isdesirable to provide a solution to identify whether an out of boundssensor reading is due to an unstable or failing subsystem or due to anexternal factor.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee. The color drawings also may be available in PAIRvia the Supplemental Content tab. The included drawings are forillustrative purposes and serve only to provide examples of possiblestructures and process operations for one or more implementations ofthis disclosure. These drawings in no way limit any changes in form anddetail that may be made by one skilled in the art without departing fromthe spirit and scope of this disclosure. A more complete understandingof the subject matter may be derived by referring to the detaileddescription and claims when considered in conjunction with the followingfigures, wherein like reference numbers refer to similar elementsthroughout the figures.

FIG. 1 shows an architectural level schematic of a system in which areagent chiller instability prediction system predicts chiller systeminstability and a flow cell heater failure prediction system detectsflow cell heater failure, both determined from newly collectedsequencing hardware sensor metrics from sequencing systems.

FIG. 2 illustrates subsystem components of reagent chiller instabilityprediction system and flow cell heater failure prediction system of FIG.1.

FIG. 3 presents examples of time series of chiller temperature sensordata before and after filtering of noisy data.

FIG. 4 is a flowchart illustrating process steps to predict reagentchiller system instability by reagent chiller failure prediction systemof FIG. 1.

FIG. 5 shows an example time series of flow cell heater temperaturesensor data before and after failure of the flow cell heater.

FIG. 6 is a flowchart of process steps for detecting flow cell heaterfailure by the flow cell heater failure prediction system of FIG. 1 withand without set point data.

FIG. 7 presents an example user interface to present results ofproactive monitoring of sequencing systems to predict hardware failures.

FIG. 8 is a simplified block diagram of a computer system that can beused to implement the reagent chiller instability prediction system andflow cell heater failure prediction system of FIG. 1.

DETAILED DESCRIPTION

The following detailed description is made with reference to thefigures. Sample implementations are described to illustrate thetechnology disclosed, not to limit its scope, which is defined by theclaims. Those of ordinary skill in the art will recognize a variety ofequivalent variations on the description that follows.

Introduction

Sequencing-by-synthesis (SBS) is one of several popular techniques forsequencing nucleotides in a DNA or RNA molecule. The machines thatperform sequencing are complex systems comprising sophisticatedsubsystems operating at specific temperatures during sequencing processsteps. The cost to acquire and operate sequencing machines is high.During the sequencing process, the subsystems of a sequencing machinecan be impacted by internal and external instabilities.

In SBS process cycles, complementary nucleotides are added one at atime, to a nucleotide sequence fragment (also called as a molecule or aninsert) from the DNA to be sequenced. Sequencing nucleotides inmolecules proceeds in hundreds of cycles. Before the sequencing cyclesbegin, a library of molecules to be sequenced is prepared on a slide ora flow cell. The molecules are arranged in tiles within multiple laneson a flow cell. A cycle includes chemical, image capture and imageprocessing actions. Subsystems, including optical, mechanical, andchemical subsystems, operate in each cycle to identify the complementarynucleotide attached to molecules. Identifying added nucleotides ismassively parallel as there are millions or billions of clusters ofmolecules on a flow cell. A sequencing run includes hundreds ofsequencing process cycles and can take multiple days to complete.Sometimes, results of an entire sequencing run are discarded becausethey do not meet the minimum quality requirements for downstreamanalysis. Therefore, it is desired to predict a subsystem failure asearly as possible if it impacts quality of sequencing results.

The technology disclosed involves modifying sequencers to exposeselected data from sensors used by internal control loops, which was notpreviously collected or analyzed. Selection of sensor data to expose andcollect required careful analysis of subsystems and sensors used incontrol loops.

Development of this technology included analysis of the newly collectedsensor data and identification of features in time series data that canbe used to predict malfunctions.

Enablement of collection of selected sensor data from many machines invarying environments with different classes of users will supportrefinement of predictive methods. Analysis of a variety of data shouldallow the development team to reduce false alerts that undermineconfidence in predictions, without missing significant events.

Sensor data collection and analysis during sequencing runs will enablean operator to abort a sequencing run that is likely to fail or toschedule preventative maintenance between runs.

Significantly, predetermined detection parameters and filters aredesigned to differentiate between error conditions and momentary,transient fluctuations due to external factors, so that false alerts donot cause runs, which should succeed, to be cancelled. For example, areagent chiller subsystem maintains precise temperature of reagents fora sequencing run. If the door of the room in which the sequencingmachine is operating is opened during summer weather, warm air fromoutside increases the room temperature. When this air enters the reagentchiller compartment, the sensor registers a higher than usualtemperature reading. This transient fluctuation should not produce anerror condition alert. In this example, an unstable or underperformingreagent chiller system produces an alert after filtering out transientfluctuations in temperatures due to external factors. In anotherexample, the technology disclosed alerts an operator to failure of aflow cell heater, using temperature data form multiple sequencingcycles. A flow cell heater that is warming too slowly can be detectedfrom temperature sensor data, in view of cycle set points or derivedthresholds. Failure of the flow cell heater to heat as expected canindicate a failing heater and/or lead to a potentially unsuccessful run.

Analysis of the newly collected sensor data during sequencing enablesgeneration of alarms and alerts to predicted failures of subsystems andsequencing runs that are likely to fail. This should reduce downtime andimprove customer satisfaction.

Environment

We describe a system for early prediction of reagent chiller failure andflow cell heater failure in sequencing systems, applied to an extendedoptical base calling process. Four types of nucleotides in a DNAmolecule are Adenine (A), Cytosine (C), Guanine (G), and Thymine (T).Base calling refers to determining a nucleotide base (A, C, G, T) percluster added to molecules in one cycle of the sequencing run. Thesystem is described with reference to FIG. 1 showing an architecturallevel schematic of a system in accordance with an implementation.Because FIG. 1 is an architectural diagram, certain details areintentionally omitted to improve the clarity of the description. Thediscussion of FIG. 1 is organized as follows. First, the elements of thefigures are described, followed by their interconnection. Then, the useof the elements in the system is described in greater detail.

FIG. 1 includes the system 100. This paragraph names the labelled partsof system 100. The figure illustrates sequencing systems (or sequencers)185, operators 113 of sequencing systems, technicians 119, a customerrelationship management (CRM) system 167, a service alerts database 141,an alerts states database 114 and a service resolution database 143. Thesystem 100 also includes a sequencing hardware sensor readings andQ-scores database 151, a configuration engine 117, and an alertingservice 121. These components contribute to a reagent chillerinstability prediction system 131 and a flow cell heater failureprediction system 141. The database 151, alerting service 121, reagentchiller instability prediction system 131, flow cell heater failureprediction system 141 can be implemented as a cloud-based proactivemaintenance analyzer 111.

The technology disclosed applies to a variety of sequencing systems 185,also referred to as sequencing instruments and sequencing platforms. Thenetwork(s) 155, couples the sequencing systems 185, the operators 113,the CRM system 167, the technicians 119, the configuration engine 117,the alerts states database 114, the alerting service 121, the reagentchiller instability prediction system 131, the flow cell heater failureprediction system 141, and database 151, in communication with oneanother. The CRM system 167 communicates with the service alertsdatabase 141 and the service resolution database 143 to send alerts tooperators 113 and technicians 119. The resolutions of the alerts afterservice by technicians are stored in service resolution database 143.The CRM system 167 can also be packaged in a customer relations module.

The sequencing systems 185 can use Illumina's sequencing-by-synthesis(SBS) technique or another sequencing technique. Illumina Inc., amanufacturer of sequencing systems 185, offers a variety of sequencingsystems including but not limited to, HISEQX™, HISEQ2500™, HISEQ3000™,HISEQ4000™, NOVASEQ6000™, and MISEQDX™. These sequencing machinesinclude a control computer, a monitor and main subsystems containing theflow cells, fluidics and reagents, optics and image capture andprocessing modules. These sequencing systems apply SBS techniques forbase calling cycles in a sequencing run. The sequencing systems 185 areused in a wide variety of physical environments ranging fromlaboratories in large research facilities to high school class rooms.Many sources of signal noise impact sequencing machines operated indiverse environments. The sequencing machines operators have a widevariety of skill levels, ranging from trained researchers in researchlaboratories to high school teachers and students using equipment onloan. Some models of sequencing machines are not highly insulated andare thus potentially impacted by weather conditions and by opening ofdoors and windows.

A sequencing run proceeds over hundreds of process cycles, ranging, forexample, from 200 to 600 cycles or 300 to 1000 cycles. Depending on theplatform, a sequencing run of 300 cycles can take up to three days tocomplete. Sometimes, a run is divided into two reads, also referred toas paired-end runs. A cycle includes chemical, image capture and imageprocessing steps. During chemical processing, a complimentary nucleotideis added to each molecule in clusters of molecules arranged in lanes onflow cells. Some subsystems are described in the following paragraphs.

A fluidics subsystem contains fluidics pumps that deliver reagents tothe flow cells and then to the waste container. A reagent is a compoundor a substance added to the flow cells in the chemical process. Racks ina reagent subsystem hold reagents in sufficient quantity for the entiresequencing run. A reagent chiller houses the reagent racks and maintainsthe internal temperature near a range of 4 degrees C. It is understoodthat in other sequencing systems, a reagent chiller can maintain adifferent temperature range.

A flow cell subsystem can include a flow cell stage, which holds theflow cell in place during sequencing runs. Some stages hold two flowcells. Heaters ramp up the flow cells to suitable reaction temperaturesduring a sequencing cycle.

The optics subsystem includes optical components that enable imaging ofthe flow cells to identify A, C, G, and T bases using fluorescentlytagged complimentary nucleotides. Excitation laser beam excites thefluorescent tags. Cameras are used to capture images that are processedto call bases. In other embodiments of sequencers, CMOS sensors overlaidby nanowells have been used as a base for a flow cell, replacingoverhead cameras.

Sequencing systems and subsystems use many sensors in control loops.System software has been updated to log selected sensor readings thatpreviously were used only for internal control loops. Sequencing systemscan be retrofitted (or initially configured), for example by deploymentof a software patch, so that a sensor reading, which was previously onlyused for internal control, will be collected and/or logged. Thecollected sensor readings can be sent to the cloud-based data proactivemaintenance analyzer 111 or stored locally to the sequencer or within anenterprise network.

In one implementation, the cloud-based proactive maintenance analyzer111 aggregates collected sensors readings. The platform directlyintegrates with sequencing machines offered. Instrument operations datacan be sent from sequencing systems 185 to cloud-based proactivemaintenance analyzer 111 via the network 155. In another implementation,a local version of the cloud-based proactive maintenance analyzer 111enables data storage and analysis onsite through an installed localserver. Operations data for a particular sequencing run from asequencing machine is stored as a data set of time series data. Theoperations data can be stored a time series of quality data, such asQ-scores for cycles and other metrics including intensity andphasing/prephasing. The quality data can be used as a dependent variablein analysis of independent sensor readings.

Data collected can be used to establish or to update predetermineddetection parameters and filters. For instance, the cloud-basedproactive maintenance analyzer collects and analyzes the time series andquality data to set or update the predetermined detection parameters.The proactive maintenance analyzer also can update the predetermineddetection parameters periodically, combining collected time series datawith service resolution data that separates correct from false alertsand indicates how an alert was resolved. Time series data from equipmentthat failed without warning also can be taken into account when updatingthe predetermined detection parameters. Both missed failures and falsealerts can be identified using the service resolution data from the CRMsystem and used to refine the predetermined detection parameters andcorresponding time series filtering.

The sequencing systems 185 report the sensor readings during orfollowing the sequencing process. They also report quality-related data.Collections of sensor and/or quality readings can be referred to aslogs. The collected sensor readings and quality data are stored indatabase 151, the sequencing hardware sensor readings and Q-scoredatabase 151. The database 151 can store time series of sensor readingsorganized according to base calling cycles per sequencing system. Thedatabase 151 can also store quality scores of the base calling cyclesper sequencing system as a dependent variable. A Q-score is a commonlyused quality score predicting the probability of an error in basecalling. Details of Q-score are presented in a technical note QualityScores for Next Generation Sequencing (2011)<accessed athttps://www.illumina.com/documents/products/technotes/technote_Q-Scores.pdfon Dec. 6, 2018>. A high Q-score indicates that a base call is morereliable and less likely to be incorrect. In one implementation,database 151 stores reagent chiller temperature and flow cell heatertemperature reported by sensors.

Several examples of quality metrics in addition to Q-scores follow. Forexample, the chemical processing subsystem generates phasing andprephasing metrics. The term “phasing” describes a situation when amolecule in a cluster of molecules falls at least one base behind othermolecules in the same cluster during sequencing process. This result maybe due to an incomplete chemical reaction. The term “prephasing”describes a situation in which a molecule jumps at least one base aheadof other molecules in the same cluster of molecules. One reason forprephasing is the incorporation of an unterminated nucleotide, andsubsequent incorporation of a second nucleotide in the same sequencingcycle. Increased phasing or prephasing detracts from accuracy of callingby confusing the luminescent signal from a cluster. Thus, phasing andprephasing measures can be used with sensor time series data to set orupdate the predetermined detection parameters.

The optics subsystem produces intensity measures that can be used asquality data. Some sequencers use cameras to capture images of clusterson flow cells during a sequencing cycle. The image acquisition includesintensity measures for cycles in a sequencing run. The process ofdetermining an intensity value for a cluster in a sequencing image isreferred to as intensity extraction. To extract intensity, a backgroundis computed for a cluster of molecules using a portion of the imagecontaining the cluster. The signal for the background is subtracted fromthe signal for the cluster to determine the intensity. The sequencinghardware sensor readings and Q-scores database 151 can store one or moreimaging performance metrics as dependent variables.

The configuration engine 117 can be used to deliver software patchesthat retrofit the sequencing system and expose sensor readings forcollection and logging. The newly collected sensor reading data isanalyzed to determine the predetermined detection parameters for thesensor readings of different sequencing system components or subsystems.After the predetermined detection parameters are determined, the sensorreadings from the sequencing systems are tested against thesepredetermined detection parameters to predict consequential subsystemmalfunctions. Further details of the configuration engine 117 andalerting service 121 are presented in the description of subsystemcomponents illustrated in FIG. 2. The reagent chiller subsystem and flowcell heater subsystem are two example subsystems of sequencing systemswhich have been retrofitted by the technology disclosed to collectsensor readings.

The reagent chiller system refrigerates reagents stored in racks withina housing to a cold temperature, such as around 4 degree Celsius for onetype of chemical process. Reagents used in the sequencing systems arechilled until used in the chemical process. Failure of the reagentchiller to compensate for fluctuations in ambient temperature can spoilreagents by exposing stored reagents to a higher than desiredtemperature for an extended period of time. The reagent chillerinstability prediction system 131 uses reagent chiller temperature datareported by a temperature sensor in reagent chiller to identifyinstabilities in operation of reagent chiller. In one implementation,software reports readings from the sensors in the reagent chiller atfive-minute intervals. It is understood that in other implementations,the temperature sensor data can be reported at time intervals greater orless than five minutes, such as in a range of 1 to 30 minutes or 30seconds to an hour. The data reported by the temperature sensor inreagent chiller can be noisy due to mechanical systems used in theoperation of the chiller subsystem. The temperature of the chillersubsystem is impacted by external factors, such as the environment inwhich the sequencing machine is operating, and by operation of thereagent chiller subsystem. The reagent chiller instability predictionsystem 131 analyzes the time series of chiller temperature sensor datato determine whether the reagent chiller system is unstable. Moredetails are presented in the description of subsystem components in FIG.2.

Flow cell heaters and chillers, respectively, heat and chill flow cellsand reagents to temperatures required for the chemical processes thatattach and remove florescent tags, which are imaged and translated intobase calls. The chemical processes proceed at different temperatures. Inone sequencing cycle implementation, the flow cell temperature is rampedup from an initial value of 20° C. to 55° C. for a brief moment and thento 60° C. for another brief moment of time. Before imaging, thetemperature of the flow cell drops back to 20° C. The temperatureramp-up and cool-down is repeated in the next sequencing cycle. Flowcell heater failure prediction system 141 analyzes the time series offlow cell heater temperature sensor data to determine if the flow cellheater has failed. The details of reagent chiller instability predictionsystem 131 and flow cell heater failure prediction system 141 arepresented in the description of subsystem components in FIG. 2.

When the failure prediction systems, such as the reagent chillerinstability prediction system 131 and flow cell heater failureprediction system 141, indicate approaching hardware failure, thealerting service 121 generates service alerts. The CRM system 167 relaysalerts that enable operators 113 and/or technicians 119 to set upservice calls for servicing the sequencing systems 185. The alerts arestored in service alerts database 141. The states of the alerts aremaintained in the alerts state database 114 to manage escalation ofservice requests in a planned manner, for example, according to servicelevel agreements. The service resolution database 143 includes detailsof the equipment service performed by the technician. Missed failuresand false alerts can be used for the purpose of adjusting thepredetermined detection parameters. Missed failures can be used as falsenegatives and false alerts can be used as false positives. For example,in flow cell heater failure prediction, false positives can indicatethat the threshold above the ambient temperature may need to beincreased. For false negatives, the threshold may need to be decreased.

Completing the description of FIG. 1, the components of the system 100,described above, are all coupled in communication the network(s) 123.The actual communication path can be point-to-point over public and/orprivate networks. The communications can occur over a variety ofnetworks, e.g., private networks, VPN, MPLS circuit, or Internet, andcan use appropriate application programming interfaces (APIs) and datainterchange formats, e.g., Representational State Transfer (REST),JavaScript Object Notation (JSON), Extensible Markup Language (XML),Simple Object Access Protocol (SOAP), Java Message Service (JMS), and/orJava Platform Module System. All of the communications can be encrypted.The communication is generally over a network such as the LAN (localarea network), WAN (wide area network), telephone network (PublicSwitched Telephone Network (PSTN), Session Initiation Protocol (SIP),wireless network, point-to-point network, star network, token ringnetwork, hub network, Internet, inclusive of the mobile Internet, viaprotocols such as EDGE, 3G, 4G LTE, Wi-Fi and WiMAX. The engines orsystem components of FIG. 1 are implemented by software running onvarying types of computing devices. Example devices are a workstation, aserver, a computing cluster, a blade server, and a server farm.Additionally, a variety of authorization and authentication techniques,such as username/password, Open Authorization (OAuth), Kerberos,SecureID, digital certificates and more, can be used to secure thecommunications.

System Components

FIG. 2 is a high-level block diagram of components configuration engine117, alerting service 121, reagent chiller instability prediction system131, and flow cell heater failure prediction system 141. These systemsare computer implemented using a variety of different computer systemsas presented below in description of FIG. 8. The illustrated componentscan be merged or further separated, when implemented.

Configuration Engine

The development team responsible for the so-called proactive alertgeneration platform investigated what data from sensors used in controlloops of sequencing machines could be logged and used to produce leadingindicators of approaching malfunctions. Sequencing systems include manysensors and software that can be updated to log a modest number ofreadings. New signals from closed loops can be identified and analysisdeveloped to yield leading indicator(s) for malfunctions.

For example, the development team determined temperature time seriesdata from the reagent chiller could yield a leading indicator ofapproaching chiller failure and reagent spoilage. The development teaminvestigated which signals to expose from sensors buried in thesequencing machines. After the signals to be collected were identified,the sequencing machines were retrofitted (and can be configured) toexpose the signals. In general, sequencing machines can be suppliedpatches using the configuration engine 117.

The configuration engine 117 comprises a patch application engine 211 todeploy software programs as patches or updates to existing softwareprogram running on the computer controlling the operations of thesequencing machine. The subsystems are computer controlled. Subsystemsof the sequencing systems contain sensors producing sensor readings thatare used in control loops during operation of the sequencing machines.New systems can be built with equivalent programming.

The newly deployed software patch enables collection and logging ofsensor data. For example, the patch application engine 211 can install asoftware patch to collect temperature sensor readings from the reagentchiller for use in the instability prediction system 131. Similarly, asoftware patch can be applied to collect flow cell heater sensorreadings for the failure prediction system 141. This part of thetechnology can also be packaged in a sensor exposing module. Theconfiguration engine 117 enables retrofitting of sequencing machines sothat previously unlogged data from the sensors in the sequencingmachines can be exposed for proactive maintenance.

The configuration engine 117 comprises a detection parameterspredetermination and update engine 212. Reliable prediction of anapproaching hardware failure involves signal analysis of collectedand/or logged sensor readings. The update engine 212 processes at leastselected log data exposed from closed loop controls. This data, whichwas not previously logged, can be collected from multiplegeographically-dispersed sequencing machines. Data can be timestamped orsequenced to facilitate correlation or it can be correlated atcollection. Data from multiple machines in independent operationsincreases reliability of the leading indicators of instrument failure.

The detection parameters predetermination and update engine 212implements the analysis prototyped by the development team, topredetermine—prior to sequencing—detection parameters and filters toapply to the time series data. Examples of analyses that can be usedinclude regression analysis, logit regression, threshold fitting tominimize a cost function and machine learning, if enough failure samplesare available. Smoothed rates of change are among the signal featuresthat can be analyzed. An analysis of the leading indicators wasperformed to determine trends in variations of leading indicators thatcan predict an approaching malfunction. The detection parameterspredetermination and update engine 212 can repeat analysis of the sensorreadings in instances of components that failed to predetermine thedetection parameters. An example of such analysis is determining thepredetermined temperature change rate in instances of the equipment withchiller systems that are approaching consequential malfunctioning.

To improve the quality of maintenance prediction alerts and reduce thenumber of false alerts, the detection parameters predetermination andupdate engine 212 could use the service resolution data, following theservice calls by the technicians 119, to update the predetermineddetection parameters. The service resolution data can includeinformation such as replacement of failed or failing components or falsepositive indications for the alerts. Existing optimization techniques,such as gradient descent or reapplication of the analyses identifiedabove, can be used to update predetermined detection parameters toreduce the numbers of missed failures and false alerts.

Updates to predetermined detection parameters can be performedperiodically after collecting of service calls records over a period oftime such as one month, three months or one to 12 months. The updateportion of the detection parameters predetermination and update enginecan also be packaged in a threshold adjustment module when it processestemperature data from reagent chillers in sequencing systems. The updateportion of the detection parameters predetermination and update enginecan also be packaged in a temperature margin adjustment module when itprocesses temperature data from flow cells in sequencing systems.

Alerting Service

Actionable alerts can be generated when failure prediction systems suchas the reagent chiller instability prediction system 131 and the flowcell heater failure prediction 141 predict an approaching malfunction.The alerts are passed to the alerting service 121. The alerting service121 includes an alert generator component 213 which implements, forinstance, a service alert subscription and publishing functionality. Thealerts are sent to operators 113 and/or technicians 119. A customerrelationship management (CRM) system can implement the alerts and trackfollow-up through resolution.

Filtering can be applied to alerts that recur over multiple cycles of asingle run and over multiple sequencing runs, especially forlaboratories that have a high utilization rate of sequencing systems185. The alert filtering engine 214 filters repeat alerts. In oneimplementation, the system maintains an alerts states database 114 toescalate the service alerts in a planned manner. The CRM system 167updates the states of the alerts through successive states, such ascreation of service ticket, scheduling of service visit and completionof equipment service. The alerting service 121 can escalate servicealerts if service actions are not completed within the required servicetimes.

The alerting service 121 can generate more than one type of alert, forexample, instrument alerts and run alerts. The instrument alerts arelong-lived, typically span across multiple runs and once an alert isgenerated it remains active until it is resolved. Instrument alerts canrequire a part replacement or repair. Examples of instrument alertsinclude reagent chiller instability, flow cell heater failure or laserpower failure. Run alerts, on the other hand, can be specific for asequencing run. In some cases, the operators 113 are able to act on suchalerts. For example, the operator can terminate the sequencing run uponreceiving an alert identifying a misalignment of the flow cell on thesequencer's flow cell holder. This can save the processing time andsequencing operation costs of a failed run.

Reagent Chiller Instability Prediction System Components

The block diagram presents example components of the two failureprediction systems 131 and 141, which predict instability of reagentchillers and failing flow cell heaters and/or chillers. The time seriespreparer component 221 is common to both systems 131 and 141. Thecomponent 221 prepares a time series from the sequencing hardwaremetrics. The time series data is collected from sensors in thesubsystems of the sequencing systems. The time series preparer 221 canalso be packaged in a log collection module. In one implementation thecollected data is uploaded to the cloud-based proactive maintenanceanalyzer 111 and stored in sequencing hardware sensor readings andQ-scores database 151. Examples of temperature sensor time series datafor reagent chillers and flow cell heaters are presented in FIGS. 3 and5. The details of components specific to the reagent chiller instabilityprediction system 131 and flow cell heater failure prediction system 141are presented in the following paragraphs.

The reagent chiller instability prediction system 131 further comprisesa data smoother 231, a time series tester 241, a severity levelidentifier 251 and a reagent chiller system stability predictor 261. Thereagent chiller temperature sensor data is chronologically sorted inascending order, if necessary, to prepare the time series. The timeseries is given as input to a data smoother component 231. As mentionedabove, the temperature data from reagent chiller is noisy. The datasmoother component 231 filters out transient oscillations in the timeseries of chiller temperature sensor data. This part of the technologydisclosed can also be packaged in a time series smoothing module. In oneimplementation, the data smoother component 231 applies a derivativefilter with a cutoff of 0.125° C. per minute to filter transientoscillations and produce a smoothed time series of chiller temperaturesensor data. Alternatively, a filter can be applied that removes thetransient oscillations that produce a rate of temperature change of0.250 degrees Celsius per minute or greater. Or, the smoothing functioncan remove transient oscillations based on a predetermined rate oftemperature change that is greater than or equal to 0.0625 degreesCelsius per minute. An upper limit such as 5.0 degrees Celsius perminute can be built into a filter, but is not necessary.

The reagent chiller prediction system 131 can be implemented as part ofthe cloud-based proactive maintenance analyzer 111. The logs oftemperature sensor data from reagent chiller are analyzed by theconfiguration engine 117 to predetermine detection parameters asdescribed above. The predetermined detection parameters are used by thetime series component 241 to predict chiller system instability. Thetime series tester component 241 tests the smoothed time series ofchiller temperature sensor data in a predefined time window for periodsof stable temperature operation. The time series tester component canalso be packaged in a temperature instability detection module. Theperiods of stable temperature operation are defined as the periods oftime during which temperature readings in the smoothed time serieschange by less than a predetermined temperature change rate using theabsolute value of the rate of change. In one implementation, theabsolute temperature change rate for stable operation is less than 0.05°C. per minute. In another implementation, a higher value can be usede.g. 0.25° C. per minute and alternatively a lower value can be usede.g. 0.01° C. per minute. If the total number of periods of stabletemperature operation in a predefined time window are less than apredetermined stability measure, the reagent chiller system stabilitypredictor component 261 determines that the chiller system is unstableand reports if the temperature is rising rapidly (i.e. faster than theabove threshold). This number of periods of stable operation can beexpressed as a predetermined percentage. The component 261 informs thealerting service 121 that the reagent chiller system is unstable. Thereagent chiller system stability predictor component 261 and thealerting service 121 can also be collectively packaged in a temperatureinstability alert module.

A severity level identifier component 251 compares the mean and mediantemperatures of a stable chiller system to two thresholds to determineseverity level 1 and severity level 2 errors. In one implementation, theconfiguration engine 117 analyzes the collected temperature sensorreadings from reagent chillers in sequencing systems to set the valuesof the thresholds. For example, such analysis for HISEQX™, HISEQ3000™,and HISEQ4000™ sequencing systems, resulted in setting of a 9° C.threshold for severity level 1 issues and a 7.5° C. threshold forseverity level 2 issues. It is understood that different thresholdvalues can be set for severity levels 1 and 2. When severity levelidentifier 251 determines a chiller system to have severity level 1 orseverity level 2 issues, it informs the alerting service 121, which canthen generate the alerts.

Flow Cell Heater Failure Prediction System Components

FIG. 2 also shows components of a flow cell heater and/or coolerprediction system 141, including a set point data separator 233, a dataanalyzer with no set point data component 243, a data analyzer with setpoint data component 253, and a flow cell heater failure predictor 263.The time series preparer component 221 retrieves temperature sensor datafor the flow cell heater from the sequencing hardware sensor readingsand Q-scores database 151. In one implementation, the time seriespreparer component 221 separates the temperature data of side A and sideB of the flow cell subsystem. In such an implementation, time series foreach side is tested separately.

The temperature sensor data for a flow cell heater is chronologicallytreated as a time series. The flow cell heater temperature sensor datacan be delimited in sequencing process cycles. A processing cycle, alsoreferred to as a base calling cycle, includes multiple chemistry processsub cycles. In one implementation, the duration of a base calling cycleis approximately 15 minutes and the duration of chemistry process subcycles is approximately 5 minutes.

In one implementation, temperature is reported from the flow cell on theorder of every minute during chemistry sub cycles during a base callingcycle. It is understood that in other implementations, samples can bereported at a higher or lower sampling rate, such as in a range of 15seconds to 3 minutes.

During chemistry process sub cycles, on one sequencer, the temperatureramps up from an initial temperature (e.g., around 20° C.) to a highertemperature (e.g., around 55° C.), stays at this temperature for a shortduration, and then ramps up to a further higher temperature (e.g.,around 60° C.) for another short duration, and then falls back toinitial temperature. These three temperature levels are referred to asset points.

In one implementation, the temperature sensor readings are sampledfurther apart than the hold duration for a specific temperature pointduring chemistry sub cycles. In such an implementation, for a smallpercentage of chemistry sub cycles, no temperature reading is taken atthe higher temperatures (55° C. and 60° C.). Therefore, beforetemperature sensor data for a processing cycle is tested by components243 or 253, it is checked whether sufficient number of temperaturesensor data readings are available. In one implementation, at least 5readings in a process cycle are required before the data is tested.Alternatively, at least 3 readings may be required or between 3 and 10readings may be required, depending on chemistry duration and sensorreporting frequency.

The flow cell heater failure prediction system 141 can be implemented aspart of the cloud-based proactive maintenance analyzer 111. Sensor datacan be analyzed with or without reported set point data. If set pointdata is available for the flow cell heater temperature sensor then thecomponent 253 analyzes the temperature sensor data using the set pointdata. There are likely to be more than one temperature set point. Theset point data separator module 233 separates the set point data timeseries from the flow cell heater temperature sensor data time series.Otherwise, if set point data is not available, then the component 243,referred to as data analyzer with no set point data, analyzes thetemperature sensor data using an operating heater threshold. Thiscomponent tests the time series of flow cell heater temperature sensordata to count measured temperature sensor data points in a recentprocess cycle that were recorded above an operating heater threshold.The threshold is determined based on the likelihood that a sensormeasurement was made during specific temperature intervals. In oneimplementation, the value of the threshold is 31° C., fairly higher thanthe ambient point, though this threshold can be set as high 54° C., justbelow the second set point, without significant change in operation. Athreshold can be used from a range 10° C. above ambient temperature upto the third set point. Multiple thresholds could be used, in place ofone threshold that tracks heating towards the second set point.

This threshold can be established from data analysis, without access todesign parameters of the system. When the temperature sensor data doesnot include set point data, the predetermined threshold analyzer used topredict flow cell heater failure is among detection parameters set bythe configuration. The configuration analyzer can use logs of flow cellheater sensor data from sequencers located at multiple locations andoperated by multiple independent operators to determine threshold(s)and/or margin(s) above and/or below ambient temperature. In oneimplementation, the configuration analyzer determines a firstpredetermined margin above ambient temperature, also referred to as athreshold. The time series from temperature sensors in flow cell heatersare tested to determine if samples in the time series are above theambient temperature by the first predetermined margin. If the data intemperature time series does not exceed the ambient temperature by thefirst predetermined margin, the flow cell heater can be failing. Morethan one consecutive time series corresponding to sequencing cycles canbe tested to predict flow cell heater failure.

During the sequencing cycles, the flow cells can also be chilled tobelow the ambient temperature. To predict the failure of the flow cellcooling to below the ambient temperature, the configuration analyzer candetermine a second predetermined margin below ambient temperature, alsoreferred to as a threshold. The configuration analyzer can use logs offlow cell heater sensor data from sequencers located at multiplelocations and operated by multiple independent operators to determinethis second margin and/or threshold. Time series from temperaturesensors in flow cell heaters are tested to determine if samples in thetime series are below the ambient temperature by the secondpredetermined margin. This testing can be early in a base calling cycle,before a predetermined count of sensor measurements during the cycle, ifchilling is at the beginning of the cycle. The flow cell heater coolingcan be predicted to be failing if the data in one or more than oneconsecutive sequencing cycles does not drop not below the ambienttemperature by the second predetermined margin, below the secondthreshold.

In a cycle, the number of sensor measurements that satisfy one or morethresholds can be counted. If the count of satisfactory temperaturesensor data points in the process cycle being evaluated is less than apredetermined count threshold, test is also applied to obtain the countof flow cell heater temperature data points for a prior (or successive)process cycle immediately preceding (or following) the recent processcycle. If the second count of satisfactory temperature data points forthe prior process cycle is less than the predetermined count threshold,in addition to the unsatisfactory first count, the flow cell heaterfailure predictor 263 determines that the flow cell heater is failingand needs to be serviced. In one implementation, the value ofpredetermined count threshold is set at 5. The predetermined countthreshold can be in a range of 1 to 1000 or higher, depending onchemistry duration and sensor reporting frequency. The component 263informs the alerting service 121 which sends the alert to a technician.The alerting service 121 can also be packaged in a temperature marginfailure alert module. The data analyzer with no set point data component243 and the flow cell heater failure predictor component 263 can becollectively packaged as a temperature margin detection module.

Data analyzer with set point data 253 compares the flow cell heatertemperature data in a recent process cycle with set point data. Like thethreshold analysis, if the temperature data is outside a predefinedallowable range of the set point data for the recent process cycle, thetemperature data for a prior cycle immediately preceding the recentprocess cycle is tested. The flow cell heater is determined to befailing if flow cell heater temperature data points for two consecutivecycles are outside the predefined allowable range of the set point data.In one implementation, the allowable range is defined as within 2° C. ofthe set point data. A predetermined count of unsatisfactory temperaturedata points can be used, as described above for thresholds.

Reagent Chiller Instability Prediction Data and Flow Chart

FIG. 3 illustrates a time series of chiller temperature sensor datacollected from eight sequencing machines M1 to M8. The horizontal axislabel indicates that six days of data are reported. The legend on thetop right corner of the graph 311 shows serial numbers (Sn1 to Sn8) ofeight machines reporting sensor data. As mentioned above, the data isnoisy. Several factors contribute to the noise in data such as operationof the mechanical systems used for cooling and condensation in thereagent chillers dripping on the temperature sensor. External factorscan also cause temperature variations such as a door of the room, inwhich the sequencing system is operating, where the door is left openwhen outside temperature is higher than room temperature. The transientoscillations of temperature, sometimes referred to as high-frequency,are removed from the time series of chiller system temperature sensordata by applying a filter. High-frequency signals have higherderivatives even if the amplitude of the signal is low, and therefore,can cause issues in signal processing. A derivative or other filter witha cut off threshold for frequency can be applied is applied to removehigh-frequency or transient oscillations in the chiller temperaturesensor data. The derivative filter also removes noise signals withfrequencies above the cut-off threshold. The clean temperature profilefor sequencing machine M1 with serial number Sn1 is shown in graph 351.In one implementation, noise is filtered out in the smoothed time series361 using the derivative filter with a cut off of 0.125° C./minute. Inanother implementation, a higher cut off value such as 0.5° C./minute isused. More generally, a smoothing filter can smooth out oscillationswith a predetermined rate of temperature change that is greater than orequal to 0.0625 degrees Celsius per minute and that is less than orequal to 0.50 degrees Celsius per minute.

Periods of steady state of chiller systems are represented by relativelyflat, horizontal portions of a smooth line on the graph. Theconfiguration engine 117 analyzes logs of time series of the temperaturesensor readings in sequencing systems with chiller system that failed todetermine the predetermined temperature change rate to predict unstablechiller systems. The predetermined detection parameters can be updatedperiodically using service logs of multiple machines. The periods ofstable temperature operation are defined as the periods of time duringwhich temperature readings in the smoothed time series change by lessthan a predetermined temperature change rate using the absolute value ofthe rate of change. In one implementation, the absolute temperaturechange rate for stable operation is less than 0.05° C. per minute. Inanother implementation, a higher value can be used e.g. 0.25° C. perminute and alternatively a lower value can be used e.g. 0.01° C. perminute, or in a range from 0.01° C. to 0.25° C. per minute. Thesteadiness criteria should not overlap with the smoothing filterparameters, or the filter will steady all data analysis.

The technology disclosed can analyze the number of periods of stableoperation, in a time window, of the chiller system to predict anunstable chiller system. In one implementation, the chiller system isconsidered in a stable operation if total time of steady state periodsis at least 14 hours in a 24 hour time window. In other implementations,time series of chiller temperature sensor data for shorter time windowscan be analyzed to identify periods of steady state, such as one to 20hours. In such implementations, the chiller system stability ispredicted by testing multiple shorter time series. The configurationengine 117 analyzes logs of time series of the temperature sensorreadings in sequencing systems with chiller system that failed todetermine the predetermined number of steady state periods in a timewindow to predict unstable chiller systems.

The graph 361 shows the temperature is increasing and crosses above the9° C. upper limit during first half of the second day (2^(nd)September). If temperature increase is due to external factors, then analarm that the chiller system is unstable should not be raised. Suppose,the increase in temperature is due to an external factor such as warmair coming in the room due to a door left opened. The temperature fallsback as the external factor is removed, such as when the door is closed.If this happens in a relatively short time, reagents are unlikely to bespoiled.

The technology disclosed differentiates between influence of externalfactors on chiller system instability, thus reducing false alerts. Inone implementation, the technology disclosed includes a predetermineddetection parameter defining for how long the chiller system is allowedto operate above the upper limit temperature (9° C.) before an alarm israised. In such an implementation, the technology disclosed observes thereversal of trends in the temperature graph 361. If analysis of data inthe graph indicates the temperature is decreasing towards the upperlimit (9° C.) then the technology disclosed determines an expected timeat which the chiller system temperature will fall back in the normaloperating temperature range. The total time a chiller system is expectedto remain above the upper limit (9° C.) is compared with the timeallowed to operate above reagent chiller upper limit. The alarm is notraised if the total expected time above the upper limit is less than thetime allowed above the upper limit. The detection parameters set by theconfiguration engine 117 are used by the reagent chiller instabilityprediction system 131 to test time series data collected fromtemperature sensors in chiller systems. The process steps can also beillustrated by a flowchart 400.

FIG. 4 is an example flowchart illustrating one implementation of thereagent chiller system stability prediction process 400. The processstarts at step 401, the temperature sensor data from sequencing hardwaresensor readings and Q-scores database 151 is given as input at step 411.As discussed above, the data includes a time series of chillertemperature sensor data. At step 421, the time series data is sortedchronologically. A derivative filter is applied at step 431 to removenoisy data. Periods of stable operation of the chiller system in apredefined time window are identified at step 341. At step 451, thecount of periods of stable operation is compared with a threshold. Ifthe count is less than the threshold, an alert is sent to the alertingservice 121 that chiller system needs service (step 450). If the countof periods of stable operation is greater than the threshold, thechiller temperature sensor data is tested for severity level 1 andseverity level 2 errors at step 361 using respective thresholds. Resultsof severity level testing are reported at step 371. The process ends atstep 381.

Flow Cell Heater Failure Prediction Data and Flow Chart

FIG. 5 includes graph 511 of an example time series of flow cell heatertemperature sensor data for a sequencing run completed in three days,with an accompanying set point time series. At the start of a processingcycle, the temperature of the flow cell is around 20° C. As thechemistry process in the cycle proceeds, the temperature of the flowcell ramps up to 55° C. for a brief moment of time and up to 60° C. foranother brief moment. At the end of the cycle, the temperature of theflow cell falls back to 20° C. and stays there until the chemistryprocess in the next cycle. This pattern of temperature ramp up and cooldown of the flow cell is repeated in each process cycle. There are threetime series of set point data as shown in the graph 511. The time seriesof set point 1 data 523 corresponds to 20° C. temperature level, thetime series of set point 2 data 615 corresponds to 55° C. and the timeseries of set point 3 data 513 corresponds to 60° C.

The graph 511 illustrates that the flow cell heater is working normallyin the beginning of the sequencing run. As the processing cyclesproceed, the flow cell temperature follows the normal operation of rampup and cool down according to the set point data (517). The current setpoint data is intended to be a time sequence that goes up and down overtime through the process. In the figure, the three set points look likecontinuous lines, because three days of data are graphed on a shorthorizontal axis, but the current set point actually goes up and down.However, the flow cell heater fails around the middle of the first dayof operation as indicated by a label 519 on the graph. After flow cellheater failure, the temperature of the flow cell remains at the ambientlevel (521) and does not follow the ramp up and cool down to three setpoints. The failure of flow cell heater results in failure of subsequentbase calling of A, G, T, and C bases as shown in the graph 551. Theintensities of the four channels corresponding to the four basesdecreases sharply at the same moment as the flow cell heater fails. Notethat temperature sensor data time series 517 and 521 as shown in graph511 represent the data from both flow cells on side A and side B. Thefailure of both flow cells at the same time is likely due to an upstreamerror (e.g., power failure, control board failure, etc.). For flow cellheater time series data that does not include set point data, thepredetermined detection parameters determined by the configurationengine 117 are used to determine the flow cell heater failure. Twoexamples of such predetermined detection parameters include, the firstpredetermined margin and the second predetermined margin as explainedabove in system description of flow cell heater failure predictionsystem (FIG. 2). The process to test the flow cell heater temperaturetime series data using the set point data or the predetermined detectionparameters is presented in the flow chart below.

FIG. 6 is an example flowchart illustrating one implementation of a flowcell heater and/or cooler failure prediction process. The process startsat step 601. The hardware metrics data is given as input at step 613. Asmentioned above the hardware metrics include flow cell heatertemperature sensor data time series and set point data time series. Theset point data time series is separated from the temperature sensor datatime series at step 623. At step 633, flow cell heater temperaturesensor data for a recent process cycle is identified. If there aresufficient data points in the recent process cycle (step 643), the flowcell heater failure prediction process continues at step 653, otherwisesteps 633 and 643 are repeated for a prior process cycle immediatelypreceding the recent process cycle. In one implementation, at least fiveflow cell heater temperature sensor data points for a process cycle arerequired to meet the condition of sufficient data points at step 543.

At step 653, it is determined whether set point data is available. Ifset point data is available, then time series of flow cell heatertemperature sensor data for the recent cycle is tested at step 655. Thetemperature data is tested to check whether it is within a predefinedallowable range of the set point data at step 663. If the data valuesare within the predefined allowable range, the control moves to step 662indicating that the flow cell heater is operating normally and does notrequire any service. Otherwise, the control moves to step 673. If setpoint data are not available, then a time series of flow cell heatertemperature sensor data is tested using a threshold using the firstpredetermined margin above the ambient temperature as defined above inFIG. 2. If count of the data points is above threshold, flow cell heaterdoes not require any service (step 662). Otherwise, the above process oftesting the temperature data points for a process cycle are repeated fora prior process cycle immediately preceding (or following) the recentprocess cycle. If the testing fails in two consecutive process cycles,it is determined that the flow cell heater requires service (step 683).The process completes at step 685.

FIG. 7 is an example user interface that can be used to present servicealerts for sequencing systems (721). The results can also indicate thenumber of alerts that resulted in hardware replacement (725) and thenumber of unique sequencing instruments for which the alerts weregenerated (729). A month-wise distribution of alerts can also bepresented graphically (763). These alerts are expected to reduceunplanned downtime of the sequencing system.

Computer System

FIG. 8 is a simplified block diagram of a computer system 800 that canbe used to implement the reagent chiller failure prediction system 131of FIG. 1 to detect chiller system instability. A similar computersystem 900 can be used to implement the flow cell heater failureprediction system 141 of FIG. 1 to detect flow cell heater failure overmultiple cycles. Computer system 800 includes at least one centralprocessing unit (CPU) 872 that communicates with a number of peripheraldevices via bus subsystem 855. These peripheral devices can include astorage subsystem 810 including, for example, memory devices and a filestorage subsystem 836, user interface input devices 838, user interfaceoutput devices 876, and a network interface subsystem 874. The input andoutput devices allow user interaction with computer system 800. Networkinterface subsystem 874 provides an interface to outside networks,including an interface to corresponding interface devices in othercomputer systems.

In one implementation, the reagent chiller failure prediction system 131of FIG. 1 is communicably linked to the storage subsystem 810 and theuser interface input devices 838. In another implementation, the flowcell heater failure prediction system 141 of FIG. 1 is communicablylinked to the storage subsystem 810 and the user interface input devices838.

User interface input devices 838 can include a keyboard; pointingdevices such as a mouse, trackball, touchpad, or graphics tablet; ascanner; a touch screen incorporated into the display; audio inputdevices such as voice recognition systems and microphones; and othertypes of input devices. In general, use of the term “input device” isintended to include all possible types of devices and ways to inputinformation into computer system 800.

User interface output devices 876 can include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem can include an LED display, a cathode raytube (CRT), a flat-panel device such as a liquid crystal display (LCD),a projection device, or some other mechanism for creating a visibleimage. The display subsystem can also provide a non-visual display suchas audio output devices. In general, use of the term “output device” isintended to include all possible types of devices and ways to outputinformation from computer system 800 to the user or to another machineor computer system.

Storage subsystem 810 stores programming and data constructs thatprovide the functionality of some or all of the modules and methodsdescribed herein. These software modules are generally executed by deeplearning processors 878.

Deep learning processors 878 can be graphics processing units (GPUs) orfield-programmable gate arrays (FPGAs). Deep learning processors 878 canbe hosted by a deep learning cloud platform such as Google CloudPlatform™, Xilinx™, and Cirrascale™. Examples of deep learningprocessors 878 include Google's Tensor Processing Unit (TPU)™, rackmountsolutions like GX4 Rackmount Series™, GX8 Rackmount Series™, NVIDIADGX-1™ Microsoft' Stratix V FPGA™, Graphcore's Intelligent ProcessorUnit (IPU)™, Qualcomm's Zeroth Platform™ with Snapdragon Processors™,NVIDIA's Volta™, NVIDIA's DRIVE PX™ NVIDIA's JETSON TX1/TX2 MODULE™,Intel's Nirvana™, Movidius VPU™, Fujitsu DPI™, ARM's DynamiclQ™, IBMTrueNorth™, and others.

Memory subsystem 822 used in the storage subsystem 810 can include anumber of memories including a main random access memory (RAM) 832 forstorage of instructions and data during program execution and a readonly memory (ROM) 834 in which fixed instructions are stored. A filestorage subsystem 836 can provide persistent storage for program anddata files, and can include a hard disk drive, a floppy disk drive alongwith associated removable media, a CD-ROM drive, an optical drive, orremovable media cartridges. The modules implementing the functionalityof certain implementations can be stored by file storage subsystem 836in the storage subsystem 910, or in other machines accessible by theprocessor.

Bus subsystem 855 provides a mechanism for letting the variouscomponents and subsystems of computer system 800 communicate with eachother as intended. Although bus subsystem 855 is shown schematically asa single bus, alternative implementations of the bus subsystem can usemultiple busses.

Computer system 800 itself can be of varying types including a personalcomputer, a portable computer, a workstation, a computer terminal, anetwork computer, a television, a mainframe, a server farm, awidely-distributed set of loosely networked computers, or any other dataprocessing system or user device. Due to the ever-changing nature ofcomputers and networks, the description of computer system 800 depictedin FIG. 8 is intended only as a specific example for purposes ofillustrating a particular implementation of the technology disclosed.Many other configurations of computer system 800 are possible havingmore or less components than the computer system depicted in FIG. 8.

The preceding description is presented to enable the making and use ofthe technology disclosed. Various modifications to the disclosedimplementations will be apparent, and the general principles definedherein may be applied to other implementations and applications withoutdeparting from the spirit and scope of the technology disclosed. Thus,the technology disclosed is not intended to be limited to theimplementations shown, but is to be accorded the widest scope consistentwith the principles and features disclosed herein. The scope of thetechnology disclosed is defined by the appended claims.

Particular Implementations Reagent Chiller Instability Prediction System

The technology disclosed relates to detection of chiller systeminstability that reduces false alerts.

The technology disclosed can be practiced as a system, method, orarticle of manufacture. One or more features of an implementation can becombined with the base implementation. Implementations that are notmutually exclusive are taught to be combinable. One or more features ofan implementation can be combined with other implementations. Thisdisclosure periodically reminds the user of these options. Omission fromsome implementations of recitations that repeat these options should notbe taken as limiting the combinations taught in the precedingsections—these recitations are hereby incorporated forward by referenceinto each of the following implementations.

A first system implementation of the technology disclosed includes oneor more processors and memory coupled to the processors. The memory isloaded with computer instructions to detect chiller system instabilityconfigured to produce fewer false alerts than a simple threshold alarm.The computer instructions, when executed on the processors, apply asmoothing function to a time series of chiller temperature sensor datato reduce transient oscillations. The transient oscillations oftemperature are sometimes referred to as high-frequency oscillations.The application of function produces a smoothed time series of chillertemperature sensor data. The system tests the smoothed time series ofchiller temperature sensor data in a predefined time window for periodsof stable temperature operation. The temperature readings in thesmoothed time series change by less than a predetermined temperaturechange rate. The system determines the chiller system to be unstablewhen less than 50 percent of the time window is stable and reports aneed for service when periods of stable temperature operation total lessthan a predetermined stability measure.

This system implementation and other systems disclosed optionallyinclude one or more of the following features. System can also includefeatures described in connection with methods disclosed. In the interestof conciseness, alternative combinations of system features are notindividually enumerated. Features applicable to systems, methods, andarticles of manufacture are not repeated for each statutory class set ofbase features. The reader will understand how features identified inthis section can readily be combined with base features in otherstatutory classes.

The system determines the predetermined temperature change rate based onequipment located at multiple locations and operated by multipleindependent operators. The system includes logic that causesconfiguration of the equipment to log and report temperature sensorreadings and store the collected logs of the temperature sensorreadings. The system includes analyzing time series of the temperaturesensor readings in instances of the equipment with chiller systems thatfailed and determines predetermined temperature change rate. Thepredetermined temperature change rate is stored for use in thedetermining of the chiller system to be unstable.

The system includes updating the predetermined temperature change ratebased on equipment located at multiple locations and operated bymultiple independent operators. The system includes logic that causesconfiguration of the equipment to log and report temperature sensorreadings. The system collects and stores logs of the temperature sensorreadings and logs of service following the notifications of theunstableness. The system includes analyzing time series of thetemperature sensor readings in instances of the equipment with chillersystems that generated the notifications and service following thenotifications. The system determines an update to the predeterminedtemperature change rate based on the analysis of the time series of thetemperature sensor readings and service record data following thenotifications. The system stores the updated predetermined temperaturechange rate for use in the determining of the chiller system to beunstable.

The system includes a cloud based proactive maintenance analyzer toaccess logs of the temperature sensor readings from a particular chillersystem. The cloud based proactive maintenance analyzer performs theapplication of the smoothing function, the determination that thesmoothed time series of chiller temperature sensor data in a predefinedtime window fails a stable temperature operation criteria and thegeneration of the notifications.

The system filters out repeat notifications and submits the filterednotifications to a customer relations management system for tracking.The system filters out repeat notifications and submits the filterednotifications to an operator of sequencer that includes the chillersystem.

There can be at least 50 multiple locations at which sequencing systemsare located. The sequencing systems can be operated by at least 20independent operators.

This system can require a higher degree of stability, applying apredetermined stability measure of 75 or 90 percent of the time window.The time window can be between four and 48 hours. One choice of timewindow can be about 24 hours. Another choice is six to 36 hours.

This system can use a derivative filter to apply the smoothing functionto the time series data. The smoothing function can be tuned to removetransient oscillations that produce a rate of temperature change of0.125 or 0.25 degrees Celsius per minute or greater. Or it can be tunedto remove transient oscillations that produce a rate of temperaturechange of greater than or equal to 0.625 degrees Celsius per minute andthat is less than or equal to 0.50 degrees Celsius per minute.

The system can use a criterion of temperature changes of less than0.010, 0.05 or 0.25 degrees Celsius per minute as the predeterminedstability measure, or in a range between any of these criteria.

The system can automatically accompany a report of a system unstablenessdetermination with the smoothed chiller system temperature sensor datafor review by a user, in either a graph or table.

The system includes comparing average and median temperatures and forperiods of stable operation and reporting a severity level 1 error abovea first threshold. The system also includes reporting a severity level 2error if the average and median temperatures for periods of stableoperation are above a second threshold.

The system includes applying the derivative filter that removestransient oscillations with a rate of absolute change of temperature ofat least 0.125 degrees Celsius per minute. The system includes testingthe smoothed time series of chiller temperature sensor data in apredefined time window for periods of stable temperature operationduring which temperature readings in the smoothed time series change byless than a predetermined absolute temperature change rate of 0.05degrees Celsius per minute.

Other implementations may include a non-transitory computer readablestorage medium storing instructions executable by a processor to performfunctions of the system described above. Yet another implementation mayinclude a method performing the functions of the system described above.

A second system implementation of the technology disclosed includes oneor more processors and memory coupled to the processors. The memory isloaded with computer instructions to detect and alert a technician thatsequencer has an unstable chiller system. The alerting system includes atime series smoothing module that receives temperature sensor data froma sensor exposed in the chiller system of the sequencer and produces asmoothed temperature time series. A temperature instability detectionmodule receives the smoothed temperature time series. The temperatureinstability detection module reports changes between smoothed successivedatum in the smoothed temperature time series that exceed apredetermined temperature change as unstable and determines a degree ofinstability. The system includes a temperature instability alert modulethat receives the reports of the degree of instability and generates analert to a technician when the degree of instability exceeds apredetermined threshold.

This system implementation and other systems disclosed optionallyinclude one or more of the following features. System can also includefeatures described in connection with methods disclosed. In the interestof conciseness, alternative combinations of system features are notindividually enumerated. Features applicable to systems, methods, andarticles of manufacture are not repeated for each statutory class set ofbase features. The reader will understand how features identified inthis section can readily be combined with base features in otherstatutory classes.

The system comprises a sensor exposing module on the sequencer thatexposes a temperature sensor in the chiller system and reportstemperature sensor data from the exposed temperature sensor. The systemincludes a log collection module that receives the temperature sensordata from multiple devices including the sequencer. The collectionmodule makes the temperatures sensor data from the chiller system of thesequencer available to the time series smoothing module.

The system can update various predetermined detection parameters for useby the alerting system. Three examples of updates to predetermineddetection parameters are presented below.

The system includes a threshold updating component that modifies thepredetermined threshold. The threshold updating component furtherincludes a log collection module and a threshold adjustment module. Thelog collection module receives the temperature sensor data from multipledevices including the sequencer. The log collection module makes thetemperature sensor data from the chiller system of the sequenceravailable to the threshold adjustment module. The threshold adjustmentmodule receives new temperature sensor data, modifies the predeterminedthreshold based on the new temperature sensor data, and stores themodified predetermined threshold for use by the temperature instabilityalert module.

The system includes a threshold updating component that modifies thepredetermined temperature change. The threshold updating componentfurther includes a log collection module and a threshold adjustmentmodule. The log collection module receives the temperature sensor datafrom multiple devices including the sequencer. The log collection modulemakes the temperature sensor data from the chiller system of thesequencer available to the threshold adjustment module. The thresholdadjustment module receives new temperature sensor data, modifies thepredetermined temperature change based on the new temperature sensordata, and stores the modified predetermined temperature change for useby the temperature instability detection module.

The system includes a threshold updating component that modifies theparameters for the smoothing module. The threshold updating componentfurther includes a log collection module and a threshold adjustmentmodule. The log collection module receives the temperature sensor datafrom multiple devices including the sequencer. The log collection modulemakes the temperature sensor data from the chiller system of thesequencer available to the threshold adjustment module. The thresholdadjustment module receives new temperature sensor data, modifies theparameters for the smoothing module based on the new temperature sensordata, and stores the modified parameters for the smoothing for use bythe time series smoothing module.

The threshold updating component and the system further comprise acustomer relations module and a threshold adjustment module. Thecustomer relations module tracks alerts, failures and resolutions formultiple devices including the sequencer. The threshold adjustmentmodule further receives failure and resolution data from the customerrelations module. It distinguishes between missed failures and falsealerts when modifying parameters used by any of the time seriessmoothing module, the temperature instability detection module, or thetemperature instability alert module.

Other implementations may include a non-transitory computer readablestorage medium storing instructions executable by a processor to performfunctions of the system described above. Yet another implementation mayinclude a method performing the functions of the system described above.

A first method implementation of the technology disclosed includesdetecting chiller system instability that reduces false alerts. Themethod includes applying a smoothing function to a time series ofchiller temperature sensor data to reduce transient oscillations. Theapplication of filter produces a smoothed time series of chillertemperature sensor data. The method includes testing the smoothed timeseries of chiller temperature sensor data in a predefined time windowfor periods of stable temperature operation. The temperature readings inthe smoothed time series change by less than a predetermined temperaturechange rate. Finally, the method determines the chiller system to beunstable and reports a need for service when periods of stabletemperature operation total less than a predetermined stability measure.

This method implementation and other methods disclosed optionallyinclude one or more of the following features. Methods can also includefeatures described in connection with systems disclosed. The reader willunderstand how features identified in this section can readily becombined with base features in other statutory classes.

The method includes determining the predetermined temperature changerate based on equipment located at multiple locations and operated bymultiple independent operators. The method includes causingconfiguration of the equipment to log and report temperature sensorreadings and store the collected logs of the temperature sensorreadings. The method includes analyzing time series of the temperaturesensor readings in instances of the equipment with chiller systems thatfailed and determining the predetermined temperature change rate. Thepredetermined temperature change rate is stored for use in thedetermining of the chiller system to be unstable.

The method includes updating the predetermined temperature change ratebased on equipment located at multiple locations and operated bymultiple independent operators. The method includes causingconfiguration of the equipment to log and report temperature sensorreadings. The method includes collecting and storing temperature sensorreadings and logs of service following the notifications of theunstableness. The method includes analyzing time series of thetemperature sensor readings in instances of the equipment with chillersystems that generated the notifications and service following thenotifications. The method includes determining an update to thepredetermined temperature change rate based on the analysis of the timeseries of the temperature sensor readings and service record datafollowing the notifications. The updated predetermined temperaturechange rate is stored for use in the determining of the chiller systemto be unstable.

The method includes accessing logs of the temperature sensor readingsfrom a particular chiller system. The method includes applying thesmoothing function to determine that the smoothed time series of chillertemperature sensor data in a predefined time window fails a stabletemperature operation criteria and the generation of the notifications.

The method includes filtering out repeat notifications and submittingthe filtered notifications to a customer relations management system fortracking. The method includes filtering out repeat notifications andsubmitting the filtered notifications to an operator of sequencer thatincludes the chiller system.

There can be at least 50 multiple locations at which sequencing systemsare located. The sequencing systems can be operated by at least 20independent operators.

The use of this method can require a higher degree of stability,applying a predetermined stability measure of 75 or 90 percent of thetime window. The time window can be between four and 48 hours. Onechoice of time window can be about 24 hours. Another choice is six to 36hours.

This method can include using a derivative filter to apply the smoothingfunction to the time series data. The smoothing function can be tuned toremove transient oscillations that produce a rate of temperature changeof 0.125 or 0.25 degrees Celsius per minute or greater. Or it can betuned to remove transient oscillations that produce a rate oftemperature change of greater than or equal to 0.625 degrees Celsius perminute and that is less than or equal to 0.50 degrees Celsius perminute.

The method can include using a criterion of temperature changes of lessthan 0.010, 0.05 or 0.25 degrees Celsius per minute as the predeterminedstability measure, or in a range between any of these criteria.

The method can include automatically accompanying a report of a systemunstableness determination with the smoothed chiller system temperaturesensor data for review by a user, in either a graph or table.

The method includes comparing average and median temperatures and forperiods of stable operation and reporting a severity level 1 error abovea first threshold. The method also includes reporting a severity level 2error if the average and median temperatures for periods of stableoperation are above a second threshold.

The method includes applying the derivative filter that removestransient oscillations with a rate of absolute change of temperature ofat least 0.125 degrees Celsius per minute. The system includes testingthe smoothed time series of chiller temperature sensor data in apredefined time window for periods of stable temperature operationduring which temperature readings in the smoothed time series change byless than a predetermined absolute temperature change rate of 0.05degrees Celsius per minute.

Each of the features discussed in this particular implementation sectionfor the system implementation apply equally to this methodimplementation. As indicated above, all the system features are notrepeated here and should be considered repeated by reference.

Other implementations may include a set of one or more non-transitorycomputer readable storage media collectively storing computer programinstructions executable by one or more processors to detect chillersystem instability. The computer program instructions when executed onor more processors implement the method including, detecting chillersystem instability that reduces false alerts. The method includesapplying a smoothing function to a time series of chiller temperaturesensor data to reduce transient oscillations. The application of filterproduces a smoothed time series of chiller temperature sensor data. Themethod includes testing the smoothed time series of chiller temperaturesensor data in a predefined time window for periods of stabletemperature operation. The temperature readings in the smoothed timeseries change by less than a predetermined temperature change rate.Finally, the method determines the chiller system to be unstable andreports a need for service when periods of stable temperature operationtotal less than a predetermined stability measure. Yet anotherimplementation may include a system including memory and one or moreprocessors operable to execute instructions, stored in the memory, toperform the first method described above.

Computer readable media (CRM) implementations of the technologydisclosed include one or more a non-transitory computer readable storagemedia impressed with computer program instructions, when executed on oneor more processors, implement the method described above.

This CRM implementation includes one or more of the following features.CRM implementation can also include features described in connectionwith system and method disclosed above. The method includes determiningthe predetermined temperature change rate based on equipment located atmultiple locations and operated by multiple independent operators. Themethod includes causing configuration of the equipment to log and reporttemperature sensor readings and store the collected logs of thetemperature sensor readings. The method includes analyzing time seriesof the temperature sensor readings in instances of the equipment withchiller systems that failed and determining the predeterminedtemperature change rate. The predetermined temperature change rate isstored for use in the determining of the chiller system to be unstable.

The CRM-implemented method includes updating the predeterminedtemperature change rate based on equipment located at multiple locationsand operated by multiple independent operators. The method includescausing configuration of the equipment to log and report temperaturesensor readings. The method includes collecting and storing temperaturesensor readings and logs of service following the notifications of theunstableness. The method includes analyzing time series of thetemperature sensor readings in instances of the equipment with chillersystems that generated the notifications and service following thenotifications. The method includes determining an update to thepredetermined temperature change rate based on the analysis of the timeseries of the temperature sensor readings and service record datafollowing the notifications. The updated predetermined temperaturechange rate is stored for use in the determining of the chiller systemto be unstable.

The CRM-implemented method includes accessing logs of the temperaturesensor readings from a particular chiller system. The method includesapplying the smoothing function to determine that the smoothed timeseries of chiller temperature sensor data in a predefined time windowfails a stable temperature operation criteria and the generation of thenotifications.

The CRM-implemented method includes filtering out repeat notificationsand submitting the filtered notifications to a customer relationsmanagement system for tracking. The method includes filtering out repeatnotifications and submitting the filtered notifications to an operatorof sequencer that includes the chiller system.

There can be at least 50 multiple locations at which sequencing systemsare located. The sequencing systems can be operated by at least 20independent operators.

The use of this method can require a higher degree of stability,applying a predetermined stability measure of 75 or 90 percent of thetime window. The time window can be between four and 48 hours. Onechoice of time window can be about 24 hours. Another choice is six to 36hours.

This CRM-implemented method can include using a derivative filter toapply the smoothing function to the time series data. The smoothingfunction can be tuned to remove transient oscillations that produce arate of temperature change of 0.125 or 0.25 degrees Celsius per minuteor greater. Or it can be tuned to remove transient oscillations thatproduce a rate of temperature change of greater than or equal to 0.625degrees Celsius per minute and that is less than or equal to 0.50degrees Celsius per minute.

The CRM-implemented method can include using a criterion of temperaturechanges of less than 0.010, 0.05 or 0.25 degrees Celsius per minute asthe predetermined stability measure, or in a range between any of thesecriteria.

The CRM-implemented method can include automatically accompanying areport of a system unstableness determination with the smoothed chillersystem temperature sensor data for review by a user, in either a graphor table.

The CRM-implemented method includes comparing average and mediantemperatures and for periods of stable operation and reporting aseverity level 1 error above a first threshold. The method also includesreporting a severity level 2 error if the average and mediantemperatures for periods of stable operation are above a secondthreshold.

The CRM-implemented method includes applying the derivative filter thatremoves transient oscillations with a rate of absolute change oftemperature of at least 0.125 degrees Celsius per minute. The systemincludes testing the smoothed time series of chiller temperature sensordata in a predefined time window for periods of stable temperatureoperation during which temperature readings in the smoothed time serieschange by less than a predetermined absolute temperature change rate of0.05 degrees Celsius per minute.

A second method implementation of the technology disclosed includesdetecting that a sequencer has an unstable chiller system. The methodincludes receiving temperature sensor data obtained from a sensorexposed in the chiller system of the sequencer. The method includesapplying a smoothing function to the temperature sensor data to producea smoothed temperature time series. The method includes determiningchanges between smoothed successive datum in the smoothed temperaturetime series that exceed a predetermined temperature change. The methodincludes determining a degree of instability based upon the determinedchanges. The method includes generating an alert indicating that thesequence has an unstable chiller system when the degree of instabilityexceeds a predetermined threshold.

This method implementation and other methods disclosed optionallyinclude one or more of the following features. Methods can also includefeatures described in connection with systems disclosed. The reader willunderstand how features identified in this section can readily becombined with base features in other statutory classes.

The temperature sensor data is determined based on sensors located atmultiple locations and operated by multiple independent operators. Themethod includes causing configuration of equipment to log and reporttemperature sensor readings. The method includes collecting logs of thetemperature sensor readings. The method includes analyzing time seriesof the temperature sensor readings in instances of the equipment withchiller systems that failed and determining the predeterminedtemperature change. The method includes storing the predeterminedtemperature change for use in the determining of the degree ofinstability.

The method further comprises, receiving the temperature sensor data frommultiple devices including the sequencer. The method includes receivingnew temperature sensor data from the multiple devices. The methodincludes modifying the predetermined threshold based on the newtemperature sensor data and storing the modified predetermined thresholdfor generating the alert.

The method further comprises, receiving the temperature sensor data frommultiple devices including the sequencer. The method includes receivingnew temperature sensor data from the multiple devices. The methodincludes modifying the predetermined temperature change based on the newtemperature sensor data. The method includes storing the modifiedpredetermined temperature change for determining changes that exceed apredetermined temperature change.

The method includes threshold updating comprising, receiving thetemperature sensor data from multiple devices including the sequencer.The method includes receiving new temperature sensor data from themultiple devices. The method includes modifying parameters for thesmoothing function based on the new temperature sensor data and storingthe modified parameters for the smoothing function.

The method includes tracking alerts, failures and resolutions formultiple devices including the sequencer. The method includes receivingfailure and resolution data from a customer relations module. The methodincludes distinguishing between missed failures and false alerts whenmodifying parameters of the smoothing function, determining a degree ofinstability, or the generating an alert.

The smoothing function is applied by a derivative filter. Applying thesmoothing function removes transient oscillations that produce a rate oftemperature change of 0.125 degrees Celsius per minute or greater.

The method includes comparing average and median temperatures forperiods of stable operation and reporting a first degree of instabilitywhen the average and median temperatures vary by more than a firstthreshold.

The method includes comparing average and median temperatures forperiods of stable operation and reporting a second degree of instabilitywhen the average and median temperatures vary by more than a secondthreshold.

A system implementation of the technology comprises one or moreprocessors coupled to memory, the memory loaded with computerinstructions that when executed by the one or more processors cause thesystem to carry out a method according to any one of methods describedabove. Each of the features discussed above in this particularimplementation section for the second method implementation applyequally to this system implementation.

A CRM implementation of the technology comprises a non-transitorycomputer readable storage media impressed with computer programinstructions. The instructions, when executed on one or more processors,implement a method according to any of the methods presented above.

Each of the features discussed in this particular implementation sectionfor the system implementation apply equally to the CRM implementation.As indicated above, all the system features are not repeated here andshould be considered repeated by reference.

Flow Cell Heater Failure Prediction System

The technology disclosed relates to detection of flow cell heaterfailure over multiple cycles in a system with no set point.

A first system implementation of the technology disclosed includes oneor more processors and memory coupled to the processor. The memory isloaded with computer instructions detecting flow cell heater failureover multiple cycles in a system with no set point. The computerinstructions, when executed on the processors, testing a time series offlow cell heater temperature sensor data across base calling cycles todetermine whether the most recent or next to most recent base callingcycle has enough flow cell heater temperature sensor data points to beevaluated. The count of cell heater temperature sensor data points thatis enough to be evaluated corresponds, in some implementations, to atime in the base calling cycles at which the flow cell heatertemperature is supposed to exceed the ambient operating temperature bymore than a first predetermined margin. The instructions further carryout determining whether latest flow cell heater temperature sensor datain the evaluated cycle exceed an ambient operating temperature by afirst predetermined margin. Upon failure of the evaluated cycle flowcell heater temperature sensor data to exceed the operating temperatureby the first predetermined margin, determining whether flow cell heatertemperature sensor data in a successive cycle, immediately following theevaluated cycle, exceed the ambient operating temperature by the firstpredetermined margin. Then, upon failure of the evaluated cycle flowcell heater temperature sensor data to exceed the operating temperatureby the first predetermined margin in both the evaluated cycle and thesuccessive cycle, determining the flow cell heater to be failing andreporting a need for service.

This system implementation and other systems disclosed optionallyinclude one or more of the following features. System can also includefeatures described in connection with methods disclosed. In the interestof conciseness, alternative combinations of system features are notindividually enumerated. Features applicable to systems, methods, andarticles of manufacture are not repeated for each statutory class set ofbase features. The reader will understand how features identified inthis section can readily be combined with base features in otherstatutory classes.

The system determines the first predetermined margin based on equipmentlocated at multiple locations and operated by multiple independentoperators. The system includes logic that causes configuration of theequipment to log and report temperature sensor readings and store thecollected logs of the temperature sensor readings. The system includeslogic to analyze time series of the temperature sensor readings ininstances of the equipment with flow cells heaters that failed anddetermines the first predetermined margin. The first predeterminedtemperature margin is stored for use in the determining of the flow cellheater to be failing.

The system updates the first predetermined margin based on equipmentlocated at multiple locations and operated by multiple independentoperators. The system includes logic that causes configuration of theequipment to log and report temperature sensor readings and logs ofservice following the reporting the need for service. The system storesthe collected logs. The system includes analyzing time series of thetemperature sensor readings in instances of the equipment with flowcells heaters that were healthy and that failed and the logs of servicefollowing the reporting of need for service. The system determines anupdate to the first predetermined margin based on the analysis.

The system includes a cloud based proactive maintenance analyzer toaccess logs of the temperature sensor readings from a particular flowcell heater. The cloud based proactive maintenance analyzer performs theapplication of the testing, the determining and the reporting the needfor service from the cloud based proactive maintenance analyzer.

The system filters out repeat notifications and submits the filterednotifications to a customer relations management system for tracking.The system filters out repeat notifications and submits the filterednotifications to an operator of sequencer that includes the flow cellheater system.

The system determines whether a count of cell heater temperature sensordata points corresponding to a time in the base calling cycles at whichthe flow cell heater temperature is supposed to exceed the ambientoperating temperature is enough to be evaluated by more than the firstpredetermined margin.

On the low side of temperatures, when the flow cell is supposed to becooled below ambient, instructions can further carry out determiningwhether one or more cell heater temperature sensor data points in theevaluated, taken prior to the count, is less wherein the ambientoperating temperature minus a second predetermined margin. Upon failureof the evaluated cycle flow cell heater temperature sensor data to beless than the operating temperature by the second predetermined margin,determining whether flow cell heater temperature sensor data taken priorto the count in a successive cycle, immediately following the evaluatedcycle, is less than the ambient operating temperature by the secondpredetermined margin. Then, upon failure of the evaluated cycle flowcell heater temperature sensor data to be less than the operatingtemperature by the second predetermined margin in both the evaluatedcycle and the successive cycle, determining flow cell cooling to befailing and reporting a need for service.

The system determines the second predetermined margin based on equipmentlocated at multiple locations and operated by multiple independentoperators. The system includes logic that causes configuration of theequipment to log and report temperature sensor readings and store thecollected logs of the temperature sensor readings. The system includesanalyzing time series of the temperature sensor readings in instances ofthe equipment with flow cells heaters that failed and determines secondpredetermined margin. The second predetermined temperature margin isstored for use in the determining of the flow cell heater to be failing.

The system updates the second predetermined margin based on equipmentlocated at multiple locations and operated by multiple independentoperators. The system includes logic that causes configuration of theequipment to log and report temperature sensor readings and logs ofservice following the reporting the need for service. The system storesthe collected logs. The system includes analyzing time series of thetemperature sensor readings in instances of the equipment with flowcells heaters that were healthy and that failed and the logs of servicefollowing the reporting of need for service. The system determines anupdate to the second predetermined margin based on the analysis.

Other implementations may include a non-transitory computer readablestorage medium storing instructions executable by a processor to performfunctions of the system described above. Yet another implementation mayinclude a method performing the functions of the system described above.

A second system implementation includes an alerting system for detectingand alerting a technician that a sequencer has a failing flow celltemperature control system. A temperature detection module analyzes atime series of flow cell temperature sensor data across base callingcycles. The temperature margin detection module determines whether themost recent or next to most recent base calling cycle has enough flowcell temperature sensor data points to be evaluated. It also determineswhether the temperature sensor data in the evaluated cycle exceeded anambient operating temperature by a first predetermined margin. Uponfailure of the evaluated cycle flow cell temperature sensor data toexceed the ambient operating temperature by the first predeterminedmargin, the flow cell temperature sensor data in a successive cycle,immediately before or following the evaluated cycle, is determined. Ifthe flow cell temperature sensor data in the successive cycle fails toexceed the ambient operating temperature by the first predeterminedmargin, the temperature margin detection module sets a first failurecondition. The system also includes a temperature margin failure alertmodule that receives the determination of the first failure conditionand that generates a flow cell heater alert to a technician.

This system implementation and other systems disclosed optionallyinclude one or more of the following features. System can also includefeatures described in connection with methods disclosed. In the interestof conciseness, alternative combinations of system features are notindividually enumerated. Features applicable to systems, methods, andarticles of manufacture are not repeated for each statutory class set ofbase features. The reader will understand how features identified inthis section can readily be combined with base features in otherstatutory classes.

The temperature margin detection module is further configured todetermine flow cell chiller failure by analyzing the time series of flowcell heater temperature sensor data across base calling cycles. Thesystem determines whether the most recent or next to most recent basecalling cycle has flow cell temperature sensor data points to beevaluated during a flow cell chilling subcycle. The system determineswhether the temperature sensor data in the evaluated cycle was chilledbelow an ambient operating temperature by a second predetermined margin.Upon failure of the evaluated cycle flow cell temperature sensor data tofall below the ambient operating temperature by the second predeterminedmargin, the system determines the flow cell heater temperature sensordata in a successive cycle, immediately before or following theevaluated cycle. If the successive cycle temperature sensors data failedto fall below the ambient operating temperature by the secondpredetermined margin, the system sets a second failure condition. Thetemperature margin failure alert module receives the determination ofthe second failure condition and generates a flow cell chiller alert toa technician.

The system includes a sensor exposing module on the sequencer thatexposes a temperature sensor in the flow cell temperature controlsystem. The sensor exposing module also reports temperature sensor datafrom the exposed temperature sensor. A log collection module receivesthe temperature sensor data from multiple devices, including thesequencer. The log collection module makes the temperature sensor datafrom the flow cell temperature control system of the sequencer availableto the temperature margin detection module.

The system includes updating the temperature margin. A log collectionmodule receives the temperature sensor data from multiple devicesincluding the sequencer. The log collection module makes the temperaturesensor data from the flow cell temperature control system of thesequencer available to a temperature margin adjustment module. Thetemperature margin adjustment module receives new temperature sensordata from the multiple devices. It modifies the first predeterminedmargin based on the new temperature sensor data, and stores the modifiedfirst predetermined threshold for use by the temperature margin failurealert module.

The system includes updating the temperature margin. A log collectionmodule receives the temperature sensor data from multiple devicesincluding the sequencer. The log collection module makes the temperaturesensor data from the flow cell temperature control system of thesequencer available to a temperature margin adjustment module. Thetemperature margin adjustment module receives new temperature sensordata from the multiple devices. It modifies the second predeterminedmargin based on the new temperature sensor data, and stores the modifiedsecond predetermined threshold for use by the temperature margin failurealert module.

The system utilizes CRM data in temperature margin updates. A customerrelations module that tracks alerts, failures and resolutions formultiple devices including the sequencer. The temperature marginadjustment module receives failure and resolution data from the customerrelations module. It distinguishes between missed failures and falsealerts when modifying parameters implemented by the temperature marginadjustment module.

Other implementations may include a non-transitory computer readablestorage medium storing instructions executable by a processor to performfunctions of the system described above. Yet another implementation mayinclude a method performing the functions of the system described above.

A first method implementation of the technology disclosed includesdetecting flow cell heater failure over multiple cycles in a system withno set point. The method includes testing a time series of flow cellheater temperature sensor data that is delimited in process cycles todetermine how many points in a recent process cycle were recorded abovea threshold. The threshold is determined based on the likelihood of themeasurement being made during specific temperature intervals. When afirst count of the points recorded in the recent process cycle is lessthan a predetermined count threshold, the method repeats the testing fora prior process cycle immediately preceding the recent process cycle anddetermines how many points in the prior process cycle were recordedabove the threshold. The threshold is determined based on the likelihoodof the measurement being made during specific temperature intervals.When a second count of the points recorded in the prior process cycle isless than the predetermined count threshold in addition to the firstcount of the points recorded in the prior process cycle is less than thepredetermined count threshold, the method determines the flow cellheater to be failing and reporting a need for service.

This method implementation and other methods disclosed optionallyinclude one or more of the following features. Methods can also includefeatures described in connection with systems disclosed. The reader willunderstand how features identified in this section can readily becombined with base features in other statutory classes.

The method includes determining the first predetermined margin based onequipment located at multiple locations and operated by multipleindependent operators. The method includes causing configuration of theequipment to log and report temperature sensor readings and store thecollected logs of the temperature sensor readings. The method includesanalyzing time series of the temperature sensor readings in instances ofthe equipment with flow cells heaters that failed and determining thefirst predetermined margin. The first predetermined temperature marginis stored for use in the determining of the flow cell heater to befailing.

The method includes updating the first predetermined margin based onequipment located at multiple locations and operated by multipleindependent operators. The method includes causing configuration of theequipment to log and report temperature sensor readings and logs ofservice following the reporting the need for service. The methodincludes storing the collected logs. The method includes analyzing timeseries of the temperature sensor readings in instances of the equipmentwith flow cells heaters that were healthy and that failed and the logsof service following the reporting of need for service. The methodincludes determining an update to the first predetermined margin basedon the analysis.

The method includes accessing logs of the temperature sensor readingsfrom a particular flow cell heater. The method includes performing theapplication of the testing, the determining and the reporting the needfor service from the cloud based proactive maintenance analyzer.

The method includes filtering out repeat notifications and submittingthe filtered notifications to a customer relations management system fortracking. The method includes filtering out repeat notifications andsubmitting the filtered notifications to an operator of sequencer thatincludes the flow cell heater system.

The method includes determining whether a count of cell heatertemperature sensor data points corresponding to a time in the basecalling cycles at which the flow cell heater temperature is supposed toexceed the ambient operating temperature is enough to be evaluated bymore than the first predetermined margin.

On the low side of temperatures, when the flow cell is supposed to becooled below ambient, instructions can further carry out determiningwhether one or more cell heater temperature sensor data points in theevaluated, taken prior to the count, is less wherein the ambientoperating temperature minus a second predetermined margin. Upon failureof the evaluated cycle flow cell heater temperature sensor data to beless than the operating temperature by the second predetermined margin,determining whether flow cell heater temperature sensor data taken priorto the count in a successive cycle, immediately following the evaluatedcycle, is less than the ambient operating temperature by the secondpredetermined margin. Then, upon failure of the evaluated cycle flowcell heater temperature sensor data to be less than the operatingtemperature by the second predetermined margin in both the evaluatedcycle and the successive cycle, determining flow cell cooling to befailing and reporting a need for service.

The method includes determining the second predetermined margin based onequipment located at multiple locations and operated by multipleindependent operators. The method includes logic that causesconfiguration of the equipment to log and report temperature sensorreadings and store the collected logs of the temperature sensorreadings. The method includes analyzing time series of the temperaturesensor readings in instances of the equipment with flow cells heatersthat failed and determining second predetermined margin. The secondpredetermined temperature margin is stored for use in the determining ofthe flow cell heater to be failing.

The method includes updating the second predetermined margin based onequipment located at multiple locations and operated by multipleindependent operators. The method includes causing configuration of theequipment to log and report temperature sensor readings and logs ofservice following the reporting the need for service. The methodincludes storing the collected logs. The method includes analyzing timeseries of the temperature sensor readings in instances of the equipmentwith flow cells heaters that were healthy and that failed and the logsof service following the reporting of need for service. The methodincludes determining an update to the second predetermined margin basedon the analysis.

Other implementations may include a set of one or more non-transitorycomputer readable storage media collectively storing computer programinstructions executable by one or more processors. The computer programinstructions when executed on or more processors implement the methodincluding, detecting that a flow cell heater is failing over multiplecycles in a base calling system. The method includes testing a timeseries of flow cell heater temperature sensor data that is delimited inprocess cycles to determine how many points in a recent process cyclewere recorded above a threshold. The threshold is determined based onthe likelihood of the measurement being made during specific temperatureintervals. When a first count of the points recorded in the recentprocess cycle is less than a predetermined count threshold, the methodrepeats the testing for a prior process cycle immediately preceding therecent process cycle and determines how many points in the prior processcycle were recorded above the threshold. The threshold is determinedbased on the likelihood of the measurement being made during specifictemperature intervals. When a second count of the points recorded in theprior process cycle is less than the predetermined count threshold inaddition to the first count of the points recorded in the prior processcycle is less than the predetermined count threshold, the methoddetermines the flow cell heater to be failing and reporting a need forservice.

This method implementation and other methods disclosed optionallyinclude one or more of the following features. Methods can also includefeatures described in connection with systems disclosed. The reader willunderstand how features identified in this section can readily becombined with base features in other statutory classes.

The CRM-implemented method includes determining the first predeterminedmargin based on equipment located at multiple locations and operated bymultiple independent operators. The method includes causingconfiguration of the equipment to log and report temperature sensorreadings and store the collected logs of the temperature sensorreadings. The method includes analyzing time series of the temperaturesensor readings in instances of the equipment with flow cells heatersthat failed and determining the first predetermined margin. The firstpredetermined temperature margin is stored for use in the determining ofthe flow cell heater to be failing.

The CRM-implemented method includes updating the first predeterminedmargin based on equipment located at multiple locations and operated bymultiple independent operators. The method includes causingconfiguration of the equipment to log and report temperature sensorreadings and logs of service following the reporting the need forservice. The method includes storing the collected logs. The methodincludes analyzing time series of the temperature sensor readings ininstances of the equipment with flow cells heaters that were healthy andthat failed and the logs of service following the reporting of need forservice. The method includes determining an update to the firstpredetermined margin based on the analysis.

The CRM-implemented method includes accessing logs of the temperaturesensor readings from a particular flow cell heater. The method includesperforming the application of the testing, the determining and thereporting the need for service from the cloud based proactivemaintenance analyzer.

The CRM-implemented method includes filtering out repeat notificationsand submitting the filtered notifications to a customer relationsmanagement system for tracking. The method includes filtering out repeatnotifications and submitting the filtered notifications to an operatorof sequencer that includes the flow cell heater system.

The CRM-implemented method includes determining whether a count of cellheater temperature sensor data points corresponding to a time in thebase calling cycles at which the flow cell heater temperature issupposed to exceed the ambient operating temperature is enough to beevaluated by more than the first predetermined margin.

On the low side of temperatures, when the flow cell is supposed to becooled below ambient, instructions can further carry out determiningwhether one or more cell heater temperature sensor data points in theevaluated, taken prior to the count, is less wherein the ambientoperating temperature minus a second predetermined margin. Upon failureof the evaluated cycle flow cell heater temperature sensor data to beless than the operating temperature by the second predetermined margin,determining whether flow cell heater temperature sensor data taken priorto the count in a successive cycle, immediately following the evaluatedcycle, is less than the ambient operating temperature by the secondpredetermined margin. Then, upon failure of the evaluated cycle flowcell heater temperature sensor data to be less than the operatingtemperature by the second predetermined margin in both the evaluatedcycle and the successive cycle, determining flow cell cooling to befailing and reporting a need for service.

The CRM-implemented method includes determining the second predeterminedmargin based on equipment located at multiple locations and operated bymultiple independent operators. The method includes logic that causesconfiguration of the equipment to log and report temperature sensorreadings and store the collected logs of the temperature sensorreadings. The method includes analyzing time series of the temperaturesensor readings in instances of the equipment with flow cells heatersthat failed and determining second predetermined margin. The secondpredetermined temperature margin is stored for use in the determining ofthe flow cell heater to be failing.

The CRM-implemented method includes updating the second predeterminedmargin based on equipment located at multiple locations and operated bymultiple independent operators. The method includes causingconfiguration of the equipment to log and report temperature sensorreadings and logs of service following the reporting the need forservice. The method includes storing the collected logs. The methodincludes analyzing time series of the temperature sensor readings ininstances of the equipment with flow cells heaters that were healthy andthat failed and the logs of service following the reporting of need forservice. The method includes determining an update to the secondpredetermined margin based on the analysis.

A second method implementation of the technology disclosed includesdetecting that a sequencer has a failing flow cell temperature controlsystem. The method includes analyzing a time series of flow celltemperature sensor data across base calling cycles. This furtherincludes determining whether a first base calling cycle has enough flowcell temperature sensor data points to satisfy a count threshold. Themethod includes determining whether the temperature sensor data in thefirst cycle exceeded an ambient operating temperature by a firstpredetermined margin. Upon failure of the flow cell temperature sensordata in the first cycle to exceed the ambient operating temperature bythe first predetermined margin, the method includes determining that theflow cell temperature sensor data in a second, contiguous cycle,immediately before or following the first cycle has enough flow celltemperature sensor data points to satisfy the count threshold. Themethod further includes determining that the flow cell temperaturesensor data in the second contiguous cycle fails to exceed the ambientoperating temperature by the first predetermined margin. The method thenresponsively setting a first failure condition. The method includesgenerating a flow cell heater alert responsive to the first failurecondition.

This method implementation and other methods disclosed optionallyinclude one or more of the following features. Methods can also includefeatures described in connection with systems disclosed. The reader willunderstand how features identified in this section can readily becombined with base features in other statutory classes.

The method includes determining flow cell chiller failure by analyzingthe time series of flow cell heater temperature sensor data across basecalling cycles. This further includes determining that the first basecalling cycle has flow cell temperature sensor data points to beevaluated during a flow cell chilling subcycle. The method includesdetermining whether the temperature sensor data in the first cycle waschilled below an ambient operating temperature by a second predeterminedmargin. Upon failure of the flow cell temperature sensor data to chillbelow the ambient operating temperature by the second predeterminedmargin in the first cycle, the method includes determining that the flowcell heater temperature sensor data in the second, contiguous cycle,immediately before or following the first cycle, failed to chill belowthe ambient operating temperature by the second predetermined margin.Following this, the method includes setting a second failure condition.The method includes generating a flow cell chiller alert responsive tothe second failure condition.

The method includes exposing a temperature sensor in the flow celltemperature control system and reporting temperature sensor data fromthe exposed temperature sensor. The method includes receiving thetemperature sensor data from multiple devices, including the sequencer.The method includes applying the analyzing a time series of flow celltemperature sensor data across a plurality of base calling cycles to thetemperature sensor data from the multiple devices.

The method including temperature margin updating, comprising, receivingthe temperature sensor data from multiple devices including thesequencer. The method further comprising receiving new temperaturesensor data from the multiple devices. The method further comprisingmodifying the first predetermined margin based on the new temperaturesensor data, and storing the modified first predetermined margin.

The method including temperature margin updating, comprising, receivingthe temperature sensor data from multiple devices including thesequencer. The method further comprising, receiving new temperaturesensor data from the multiple devices. The method including modifyingthe second predetermined margin based on the new temperature sensordata, and storing the modified second predetermined margin.

The method utilizing CRM data in temperature margin updating,comprising, tracking alerts, failures and resolutions for multipledevices including the sequencer. The method further comprising,receiving failure and resolution data from the customer relations moduleand distinguishing between missed failures and false alerts whenmodifying parameters implemented by the temperature margin adjustmentmodule.

A system implementation of the technology comprises one or moreprocessors coupled to memory, the memory loaded with computerinstructions that when executed by the one or more processors cause thesystem to carry out a method according to any one of methods describedabove. Each of the features discussed above in this particularimplementation section for the second method implementation applyequally to this system implementation.

A CRM implementation of the technology comprises a non-transitorycomputer readable storage media impressed with computer programinstructions. The instructions, when executed on one or more processors,implement a method according to any of the methods presented above.

Each of the features discussed in this particular implementation sectionfor the system implementation apply equally to the CRM implementation.As indicated above, all the system features are not repeated here andshould be considered repeated by reference.

We claim as follows:
 1. A method of detecting chiller system instabilitycomprising: applying a smoothing function to a time series of chillertemperature sensor data and reducing transient oscillations to produce asmoothed time series of chiller temperature sensor data; determiningthat the smoothed time series of chiller temperature sensor data in apredefined time window fails a stable temperature operation criteria intime intervals during which temperature readings in the smoothed timeseries change by more than a predetermined temperature change rate frominterval to interval; and generating a notification of unstableness whenthe smoothed time series of chiller temperature sensor data fails thestable temperature operation criteria in more than a predeterminedpercentage of the time intervals over the predefined time window.
 2. Themethod of claim 1, further comprising: determining the predeterminedtemperature change rate based on equipment located at multiple locationsand operated by multiple independent operators, including: causingconfiguration of the equipment to log and report temperature sensorreadings; collecting logs of the temperature sensor readings; analyzingtime series of the temperature sensor readings in instances of theequipment with chiller systems that failed and determining thepredetermined temperature change rate; and storing the predeterminedtemperature change rate for use in the determining of the chiller systemto be unstable.
 3. The method of claim 1, further comprising: updatingthe predetermined temperature change rate based on equipment located atmultiple locations and operated by multiple independent operators,including: causing configuration of the equipment to log and reporttemperature sensor readings; collecting logs of the temperature sensorreadings and logs of service following the notifications of theunstableness; analyzing time series of the temperature sensor readingsin instances of the equipment with chiller systems that generated thenotifications and service following the notifications; determining anupdate to the predetermined temperature change rate based on theanalyzing; and storing the updated predetermined temperature change ratefor use in the determining of the chiller system to be unstable.
 4. Themethod of claim 1, further comprising: accessing logs of the temperaturesensor readings from a particular chiller system in a cloud basedproactive maintenance analyzer; and performing the applying, thedetermining and the generating the notification from the cloud basedproactive maintenance analyzer.
 5. The method of claim 4, furthercomprising filtering notifications for repeat notification andsubmitting the filtered notifications to a customer relations managementsystem for tracking.
 6. The method of claim 4, further comprisingfiltering notifications for repeat notification and submitting thefiltered notifications to an operator of sequencer that includes thechiller system.
 7. The method of claim 2, further including determiningthe predetermined temperature change rate based on equipment located atthe multiple locations and operated by the multiple independentoperators, wherein the multiple locations include at least 50 locationsand the multiple independent operators include at least 20 independentoperators.
 8. The method of claim 1, wherein the smoothing function isapplied by a derivative filter.
 9. The method of claim 1, whereinapplying the smoothing function removes transient oscillations thatproduce a rate of temperature change of 0.125 degrees Celsius per minuteor greater.
 10. The method of claim 1, wherein the time series datarepresents between four hours and 48 hours of chiller temperature sensordata.
 11. The method of claim 1, further including automaticallypresenting the smoothed chiller system temperature sensor data forreview by a user when presenting the system unstableness determination.12. The method of claim 1, further including comparing average andmedian temperatures for periods of stable operation and reporting aseverity level 1 error when the average and median temperatures vary bymore than a first threshold.
 13. The method of claim 1, furtherincluding comparing average and median temperatures for periods ofstable operation and reporting a severity level 2 error when the averageand median temperatures vary by more than a second threshold.
 14. Asystem including one or more processors coupled to memory, the memoryloaded with computer instructions to detect chiller system instability,the instructions, when executed on the processors, implement actionscomprising: applying a smoothing function to a time series of chillertemperature sensor data and reducing transient oscillations to produce asmoothed time series of chiller temperature sensor data; determiningthat the smoothed time series of chiller temperature sensor data in apredefined time window fails a stable temperature operation criteria intime intervals during which temperature readings in the smoothed timeseries change by more than a predetermined temperature change rate frominterval to interval; and generating a notification of unstableness whenthe smoothed time series of chiller temperature sensor data fails thestable temperature operation criteria in more than a predeterminedpercentage of the time intervals over the predefined time window. 15.The system of claim 14, further implementing actions comprising:determining the predetermined temperature change rate based on equipmentlocated at multiple locations and operated by multiple independentoperators, including: causing configuration of the equipment to log andreport temperature sensor readings; collecting logs of the temperaturesensor readings; analyzing time series of the temperature sensorreadings in instances of the equipment with chiller systems that failedand determining the predetermined temperature change rate; and storingthe predetermined temperature change rate for use in the determining ofthe chiller system to be unstable.
 16. The system of claim 14, furtherimplementing actions comprising: updating the predetermined temperaturechange rate based on equipment located at multiple locations andoperated by multiple independent operators, including: causingconfiguration of the equipment to log and report temperature sensorreadings; collecting logs of the temperature sensor readings and logs ofservice following the notifications of the unstableness; analyzing timeseries of the temperature sensor readings in instances of the equipmentwith chiller systems that generated the notifications and servicefollowing the notifications; determining an update to the predeterminedtemperature change rate based on the analyzing; and storing the updatedpredetermined temperature change rate for use in the determining of thechiller system to be unstable.
 17. The system of claim 14, furtherimplementing actions comprising: accessing logs of the temperaturesensor readings from a particular chiller system in a cloud basedproactive maintenance analyzer; and performing the applying, thedetermining and the generating the notification from the cloud basedproactive maintenance analyzer.
 18. The system of claim 17, furtherimplementing actions comprising: filtering notifications for repeatnotification and submitting the filtered notifications to a customerrelations management system for tracking.
 19. The system of claim 17,further implementing actions comprising: filtering notifications forrepeat notification and submitting the filtered notifications to anoperator of sequencer that includes the chiller system.
 20. A set of oneor more non-transitory computer readable storage media collectivelyimpressed with computer program instructions to detect chiller systeminstability, the instructions, when executed on one or more processors,implement a method comprising: applying a smoothing function to a timeseries of chiller temperature sensor data and reducing transientoscillations to produce a smoothed time series of chiller temperaturesensor data; determining that the smoothed time series of chillertemperature sensor data in a predefined time window fails a stabletemperature operation criteria in time intervals during whichtemperature readings in the smoothed time series change by more than apredetermined temperature change rate from interval to interval; andgenerating a notification of unstableness when the smoothed time seriesof chiller temperature sensor data fails the stable temperatureoperation criteria in more than a predetermined percentage of the timeintervals over the predefined time window.
 21. The set of one or morenon-transitory computer readable storage media of claim 20, wherein thesmoothing function is applied by a derivative filter.
 22. The set of oneor more non-transitory computer readable storage media of claim 20,wherein applying the smoothing function removes transitory oscillationsthat produce a rate of temperature change of 0.125 degrees Celsius perminute or greater.
 23. The set of one or more non-transitory computerreadable storage media of claim 20, wherein the time series datarepresents between four hours and 48 hours of chiller temperature sensordata.
 24. The set of one or more non-transitory computer readablestorage media of claim 20, implementing the method further comprising:comparing average and median temperatures for periods of stableoperation and reporting a missed failure when the average and mediantemperatures vary by more than a first threshold.
 25. The set of one ormore non-transitory computer readable storage media of claim 20,implementing the method further comprising: comparing average and mediantemperatures for periods of stable operation and reporting a false alertwhen the average and median temperatures vary by more than a secondthreshold.